Fix instruction duration unit in estimated success probability calculation (#445)

## Description

Fixes instruction duration unit in estimated success probability
calculation in `src/mqt/predictor/reward.py`, as the default unit is
`"dt"` instead of `"s"`:
[https://github.com/Qiskit/qiskit/blob/stable/2.1/qiskit/transpiler/target.py#L415-L430](url)

Author: Shaobo-Zhou

CHANGELOG.md

@@ -11,6 +11,7 @@ This project adheres to [Semantic Versioning], with the exception that minor rel
 
 ### Changed
 
+- 🐛 Fix instruction duration unit in estimated success probability calculation ([#445]) ([**@Shaobo-Zhou**])
 - ✨ Remove support for custom names of trained models ([#489]) ([**@bachase**])
 - 🔥 Drop support for x86 macOS systems ([#421]) ([**@denialhaag**])
 
@@ -44,6 +45,7 @@ _📚 Refer to the [GitHub Release Notes](https://github.com/munich-quantum-tool
 
 <!-- PR links -->
 
+[#445]: https://github.com/munich-quantum-toolkit/predictor/pull/445
 [#489]: https://github.com/munich-quantum-toolkit/predictor/pull/489
 [#421]: https://github.com/munich-quantum-toolkit/predictor/pull/421
 [#406]: https://github.com/munich-quantum-toolkit/predictor/pull/406
@@ -61,6 +63,7 @@ _📚 Refer to the [GitHub Release Notes](https://github.com/munich-quantum-tool
 [**@flowerthrower**]: https://github.com/flowerthrower
 [**@denialhaag**]: https://github.com/denialhaag
 [**@bachase**]: https://github.com/bachase
+[**@Shaobo-Zhou**]: https://github.com/Shaobo-Zhou
 
 <!-- General links -->
 

src/mqt/predictor/reward.py

@@ -203,8 +203,10 @@ def estimated_success_probability(qc: QuantumCircuit, device: Target, precision:
                 if first_qubit_idx not in active_qubits:
                     continue
 
+                dt = device.dt  # instruction durations are stored in unit dt
                 res *= np.exp(
                     -instruction.duration
+                    * dt
                     / min(device.qubit_properties[first_qubit_idx].t1, device.qubit_properties[first_qubit_idx].t2)
                 )
                 continue